Reset stylesheet (via Eric Meyer) the goal of a reset stylesheet is “to reduce browser inconsistencies” see here for a deeper explanation, again solves many many issues and enables a new build to start from the same starting point on every browser by resetting common element behaviour.

Also, avoid/beware overuse of widths, heights, margins (esp with floats), too many position: relative’s (esp. nested position:relatives), widths + heights + padding + margin (box model issues, add padding/margin to fixed-width child elements). There are many more issues and many other ways to solve them, but generally most can be solved via fairly well documented locations, a good one here, otherwise search on google.